Photonic crystals based on opal structures

We have studied the transmission of electromagnetic waves in opals partially and completely infilled by semiconductor materials. The sintering process used to stabilize opals is found to increase the transmission along the [111] direction. We have shown that for increasing thickness of coating, the L-gap first closes for a small relative coating thickness 4% before to progressively broaden up to 33% of the midgap frequency for complete infilling. The second incomplete gap in the [100] is nearly closed for bare and complete opals and reaches its maximum value for an intermediate coating. These results shows that opals could be good candidates for inhibition of transmission for photonic devices.